Adsorption of 4,6-Dimethyldibenzothiophene over Cu/ZrO₂

The adsorption of refractory sulfur molecule 4,6-Dimethyldibenzothiophene (4,6-DMDBT) over copper supported on zirconia, using different copper loadings (2-10% w/w) and a zirconia support with a high specific surface area, was studied. The results showed that the adsorption capacity of 4,6-DMDBT over Cu/ZrO₂increased with copper content, reaching a maximum at around 8% Cu (0.58 mmol 4,6-DMDBT per gram of adsorbent). The results of characterizations with H₂- TPR, Electrophoretic Migration, and XRD demonstrated that this Cu loading (8%) also corresponds to a maximum copper dispersion capacity for ZrO₂support. Also, these absorbents showed considerable selectivity toward the adsorption of 4,6-DMDBT in a feed stream also containing Quinoline, decreasing adsorption capacity of 4,6-DMDBT by only 35%, despite both molecules being present in the same concentrations. The results of this work showed that desulfurization adsorption using Cu/ZrO₂ adsorbents can be an effective method to remove this type of refractory sulfur molecules, and an excellent alternative as a complementary process for deep desulfurization in the fuel industry.